It is known, e.g. from German application No. 2,309,032 published Sept. 5, 1974 and corresponding to U.S. Pat. No. 3,933,598, to hold such a sealing frame in position by recessed clamping plates which are mounted on the outer surface of a peripheral flange of the door, the flange being traversed by bolts that pass through slots of the clamping plates for enabling the adjustment of these plates--jointly with the engaged sealing frame--in a direction perpendicular to the door opening of the coking chamber. As further taught in that German application, the plates have outwardly extending lugs or ledges serving as guides for respective rods which engage the web of the sealing frame in the vicinity of its free knife edge, biasing that knife edge under spring pressure toward the confronting door frame. Additional screws on the door flange serve to backstop the clamping plates, and with them the rim of the sealing frame, against the contact pressure existing between the knife edge and the door frame in the working position of the door.
The arrangement described in the German application is designed to insure optimum contact between the door frame and the knife edge of the sealing frame all around the door opening and, by suitable local adjustments, to compensate for thermal and other deformations of the door structure. These adjustments, however, are rather complicated to perform since any shift of a clamping plate must be preceded by a loosening of the corresponding mounting bolts, a resetting of the associated backstopping screw and, finally, a retightening of the mounting bolts.